That’s probably a mistake — even if you already have retirement savings. You’re losing all future growth in this account! But I assume you have some current use for the money.
Unless the current retirement account is a SEP or SEP-IRA, you won’t be charged a penalty for early withdrawal if you leave the company. But you will find that amount added to your ordinary income, and it might move you into a higher bracket.
For details, read THIS from the IRS>