pass muster as sth

meaning be accepted as good enough for sth. [1]
e.g., I hope I'll be pass muster as a candidate for software engineer.
PS: pass verb; muster N-count.

step into the breach

meaning help by doing someone else' job or work when they are unable to do it.

take the floor

take (to) the floor (=begin dancing)
take the floor == begin speaking at an important public meeting.
e.g., Once I take the floor, I feel nervous.

参考资料

[1] 朗文词典第五版（Longman dictionary） https://www.ldoceonline.com/