Initial gamble when climbing in potentially explosive location (4)

I believe the answer is:

ante

I'm a little stuck... Click here to teach me more about this clue!

'initial gamble' is the definition.
'ante' can be an answer for 'gamble' (ante is a kind of gamble). I am unsure of the 'initial' bit.

I don't understand the remainder of the clue.

Can you help me to learn more?

(Other definitions for ante that I've seen before include "Player's stake in poker - a ten? (anag)" , "Gaming stake" , "Card-player's stake" , "Advance stake" , "Poker-player's stake before the deal" .)

I've seen this clue in The Irish Times.

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