What to do when surrounded by more than one enemy in Free Fire?

You just can't take them on like that. Firstly, use everything you have, pick up any gun around you and start a counter-offensive. Aim for their heads (goes without saying).

Deliver them serious damage, you know the panic when someone suddenly gives you a damage of over 80. It should discourage them from engaging you.

Next, as @vigneshrawan pointed, use Gloo walls judiciously. They can make a great difference.

You might even like a flashbang, and run in a pre-designated direction because the screen is gonna go white once it goes off, buying you time to hide, simply prone or find cover.

Use your character's special abilities such as Kla for a headshot punch or Kelly's sprinting to run. Run towards the shooter in a zig-zag way. Avoid sprinting here. My friend a guy with MP-40 with bare hands as the guy could barely aim with him jumping around and breaking into a run and stopping suddenly.

If you lose serious HP, like 100 or something then, prone and use med-kit, even if you don't use it right then, you are likely to die but if so your enemy, keep shooting.In the end, it is better to weigh your chances and see what fits the situation best.

If you can find a vehicle, get in it and run away. With a med-kit then, even better as even vehicles get easily damaged.

Lastly, if you have nothing, improvise, sprint around, confuse the enemies, frustrate them by jumping, suddenly starting and crouching; do whatever it takes to win and of course, have fun.

Hope this helps and we see each other in the battleground.

get stronger armor and better artillery. Kill as many as you can, and escape. Find some sort of cover, anywhere you can.