I took my sweet ass time on that chapter and it was fun. Only tip that I found needed was basically lay down like 4 explosive bolts for him. I stay at opposite side of ladder so I lay a trail from the ladder to opposite side and he will follow path to get to me.
Up to chapter 13, finally having fun and getting the hang of it. Sneaking past the Keeper is tense! The garage monster took couple tries but wasn't so bad, use rifle and like you said flash and freeze. If anyone interested, found some good tips online to avoid rage quit like me
1. Shoot legs to drop enemy and light em up with match. This even works on the fake Ruvik with just a pistol and 1 or 2 rounds. I have full critical and weapon sway on pistol, point blank on the headshot and it still misses. The aiming mechanics is my main complaint.
2. Fully upgrade flash bolts to 16s and sneak kill. So satisfying and save mucho ammo, wish I did this earlier.
3. Fully upgrade matches or at least 15, I did this first and its useful in later chapters.
4. I did not upgrade melee, health, syringe or weapon damage at all (except pistol critical) and I am doing fine. I would save gel for the above.