Achievement Help: Taking down the big top and assistant homiside

[Raccoon99]

Note: this is my 1st thread here.
I need help on getting these 2 achievements. If anyone could give me advice, that would help. My zerk is lvl 2.

Taking down the Big top: Oh Boy. Its either my game was about to crash, Zed time was not active or was active at the wrong time or Running out too fast. this is the one i have most trouble with.

Assistant Homiside: Either the guy kills the stalkers before i do or the stalkers go for me at the last sec.