Any firefighter who shall have served for a period of less than twenty-five years, or who shall be less than fifty years of age, and shall resign, or be dismissed from the fire department for a reason other than conviction for a felony, shall be paid the amount of his or her contributions to the fund plus earned interest: PROVIDED, That in the case of any firefighter who has completed twenty years of service, such firefighter, upon termination for any cause except for a conviction of a felony, shall have the option of electing, in lieu of recovery of his or her contributions as herein provided, to be classified as a vested firefighter in accordance with the following provisions:
(1) Written notice of such election shall be filed with the board within thirty days after the effective date of such firefighter's termination;
(2) During the period between the date of his or her termination and the date upon which he or she becomes a retired firefighter as hereinafter provided, such vested firefighter and his or her spouse or dependent children shall be entitled to all benefits available under chapter
41.18 RCW to a retired firefighter and his or her spouse or dependent children with the exception of the service retirement allowance as herein provided for: PROVIDED, That any claim for medical coverage under RCW
41.18.060 shall be attributable to service connected illness or injury;
(3) Any firefighter electing to become a vested firefighter shall be entitled at such time as he or she otherwise would have completed twenty-five years of service had he or she not terminated, to receive a service retirement allowance computed on the following basis: Two percent of the amount of salary attached to the position held by the vested firefighter for the year preceding the date of his or her termination, for each year of service rendered prior to the date of his or her termination.