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
95,183.94
-1.02%

ETH
3,283.06
-0.56%

XRP
2.0528
-1.21%