It's not Slimy's speed and agility at question, but its sensory capacity.
The Machine is not so indestructible as it seems apparently, your character has already demonstrated the capacity to muscle its way through armour of the exact same thickness as the joints of the Mech. However rather than press your speed advantage and try for more attacks you insist upon maximum damage from the first? Why is that exactly? What a boring fight you seem to desire.
Meta-gaming would suggest Higan had absolutely no way of knowing that the creature was in hiding, I'm not a soldier, but I think even I could have guessed where Slimy would be hidden considering what greeted him upon entering the room. Here's my break down, as you seem unable to see how observational skills and things I literally state Higan as picking out in the battle can account for his actions.
1. He literally sees Slimy demonstrate the ability to disguise itself from Electric vision.
2. He walks into the most obvious 'I live here' room of all time and has plenty of ammunition, why wouldn't he expend it trying to flush the creature out?
3. He's a soldier, trained to check his corners as every soldier is, it's literally the first place soldiers soldier when entering a room, and you hid there. You know what Higan would have been more surprised by? If you had hid on the ceiling, directly above him.
No, you should be grateful I had him unnecessarily fire his sniper-rifle out of a cheery sporting attitude, he fired it to 'scatter the birds' so to speak. He could have just have easily have sprayed the room with chain-gun fire and blasted a hole through Slimy as he charged.
No, you misunderstand. The Sniper-rifle is a massive metallic pole and the Mech is weighty as hell and super-strong, he literally pointed it at Slimy with the intent of warding him off physically, and you completely ignored the impediment and flew past it. Considering the ground Slimy had to cover his speed and agility was not sufficient to warrant completely ignoring the move, and the distance had to be significant, as he avoided the explosion from the anti-tank round a few moments before. Here's my post where I graciously accept you completely ignored the defence and carried on.
http://www.roleplayerguild.com/posts/3381249Their success speaks only of your own lapse into meta-gaming, whereby Slimy carried out a move completely different to its original objective of climbing up the Mech's back, almost as if it read Higan's mind. Even you had to accept you'd bullshitted that move and had the tail take damage, even though it probably should have been Slimy's actual body.
I've already explained how Higan knew where Slimy was going to be quite conclusively. Though you obviously ignored that argument, as you have proven to do whenever you can't think of a retort. To re-iterate, he threw the Mech backwards, cutting off Slimy's hiding spots, he saw it on the Mech's leg, he knew it was still there, there was only one spot remaining if Slimy was on the Mech at all. If the chain-gun had simply kept firing Slimy would have been wiped off the top of the Mech the moment the hand was in position, but I decided to go for a grab for reasons already mentioned.
Try harder, troll harder, troll faster.