A short position means that the trader was betting on the price of Bitcoin $BTC decreasing.
When the price moves against the short (in this case, it increased to $94,570.90), the trader is forced to close their position to prevent further losses, leading to liquidation.
The amount of $50.4K could refer to the size of the short position, the loss incurred, or the value of the liquidation.

BTC
65,972.89
-0.74%

ETH
1,984.44
-0.56%

XRP
1.3276
-0.48%