The 名詞（めいし） (noun) 手前（てまえ） ‘in front of’ has several different meanings in Japanese depending on whether it is being used with a verb in its 普通形（ふつうけい） (standard form), or with a noun.
Regarding verbs, it expresses ‘going forward from (A), (B)’. This is usually in relation to something that has happened either accidentally or completely, and may represent what will be done as a result of being in that situation.

• 崖（がけ）から落（お）ちる手前（てまえ）で父親（ちちおや）に腕（うで）を引（ひ）っ張（ぱ）られた。
  My father pulled me by my arm before I fell off the cliff.
• 勢（いきお）いで手（て）を上（あ）げてしまった手前（てまえ）、答（こた）えずに手（て）を下（さ）げるわけにはいかない。
  From the standpoint of me raising my hand in the heat of the moment, there is no way of me backing out without answering the question.
• 先輩（せんぱい）にはいつもお世話（せわ）になっている手前（てまえ）、彼女（かのじょ）の頼（たの）みを断（ことわ）るわけにはいかない。
  Since my senpai always takes good care of me, there is no way that I can turn down her favor.

This can also be interpreted as ‘now that (A), (B)’, and simply highlights that nothing can be done except to move on or ‘forward’ given the current circumstances.
When 手前（てまえ） appears with nouns followed by the 格助詞（かくじょし） (case-marking particle) の, it often expresses that what is ‘in front’ of (A) is the reason for (B), or simply is ‘in front of (B)’.

• 娘（むすめ）の手前（てまえ）、運動（うんどう）音痴（おんち）な姿（すがた）を見（み）せるわけにはいかない。
  In front of my daughter, I couldn't let her see me being athletically inept.
• 彼女（かのじょ）の両親（りょうしん）の手前（てまえ）、発言（はつげん）には気（き）を付（つ）けなければいけない。
  I have to be careful of what I say when I am in front of my girlfriend’s parents.

Despite the many translations, 手前（てまえ） always shows something that is ‘facing’ the noun or verb that appears with it. Due to this, thinking of this structure as similar to ‘faced with (A), (B)’ may be helpful, as English also expresses lack of option and finality in this way.